Voice over Internet protocol (VoIP) implementations enable voice traffic, such as telephone calls, to be carried over Internet protocol (IP) communications networks. This allows voice calls to leverage the reduced transmission cost of packet switched networks to carry information that was once exclusively carried over more expensive conventional circuit switched networks. During a VoIP call, the voice signal of a VoIP call is compressed and packetized using one or more protocols so as to be suitable for transmission over a packet switched communications network (e.g., the Internet) to the called party. When VoIP packets are received at their destination, the voice signal is decompressed before being played to the called party. The specific path that the packets take over a packet switched communications network varies and, therefore, a VoIP call between the same origin and destination may take different paths through the communications network. As a result, voice call quality for VoIP calls may vary more than for conventional calls transmitted over a circuit switched network. Exemplary factors that may affect VoIP call quality may include packet delay, jitter, and loss. The importance of maintaining consistently high call quality for VoIP calls is especially important because service providers may enter into contracts with customers to provide specified levels of speech quality between specified endpoints.
In order to better evaluate VoIP call quality, various measures of speech quality have been used for monitoring speech quality for VoIP calls. These measures can be generally divided into objective and subjective measures of voice quality for ensuring that a specified voice quality level is being met. Objective measures of speech quality may include, for example, monitoring the number of packets being dropped compared to an acceptable threshold value. Objective measures of speech quality have the advantage of being fully computer-implementable, and therefore fully automatable and reliable. However, because speech quality is fundamentally a judgment perceived by human users rather than machines, many purely objective measures fail to correlate with subjective measures of speech quality. As a result, subjective measures of speech quality have also been developed. For example, one conventional subjective speech quality measure includes a mean opinion score (MOS) for a call. The MOS for a call may be determined by judging the voice quality of a call using a variety of human listeners, whose judgments may be expressed on a scale of 1 (bad) to 5 (excellent). While subjective measures may provide a more accurate indication of speech quality as perceived by a human user, they may nonetheless lack some of the advantages associated with objective speech quality measures described above.
More recently, an algorithm known as perceptual evaluation of speech quality (PESQ) has been developed which more accurately matches the perceived quality scores determined using subjective measures while still being based on objective measures. A primary reason for the success of PESQ as a call quality evaluation tool is that PESQ is capable of accounting for filtering, variable delay, and short localized distortions of packetized voice calls common to VoIP calls. As a result, PESQ is a popular measure of end-to-end voice quality over packet switched networks. Specifically, a PESQ score is an estimation of speech quality that is expressed on a scale of −0.51 (bad) to 4.5 (excellent) based on objective criteria such as packet delay, jitter, and loss. PESQ compares an original signal X(t) with a degraded signal Y(t) that is the result of passing X(t) through a communications system by placing one or more test calls to a subscriber device such as a cable or DSL modem. The output of PESQ is a prediction of the perceived quality that would be given to Y(t) in a subjective listening test. When PESQ or similar algorithms are used to measure speech quality, a dedicated voice call is set up to transmit only test speech signals over a communications network. This enables the test voice signals to be easily identified and provides a means of determining the amount of degradation that occurs as a result of transmission over the network. PESQ provides an estimate of the speech quality and is described in international telecommunications union (ITU) recommendation P.862, the content of which is incorporated herein by reference in its entirety. In addition to test call data, IP metrics may be maintained for calls placed by or received by subscribers. IP metrics may include objective values such as jitter, latency, and packet loss which may be obtained from one or more call detail records (CDRs).
In addition to VoIP data, service providers may maintain geographical information describing the physical location of network devices and endpoints within the network. For example, street addresses and global positioning system (GPS) coordinates for each switch, router, hub site, node, and/or modem may be maintained so that the physical location of every entity in the service provider's network is known.
However, one problem associated with conventional methods for monitoring voice quality in packet switched networks is that test call data and geographical information are separately maintained. As a result, physical relationships between test call errors and/or successes may be obscured from the service provider and, as such, operators may be slow to identify and correct network problems affecting VoIP call quality.
Accordingly, in light of these difficulties, a need exists for improved methods, systems, and computer readable media for combining VoIP call data with geographical information and displaying it to a user.